from: https://patchwork.kernel.org/project/linux-mediatek/patch/20210720100553.2340425-1-pihsun@chromium.org/
      [v2] drm/bridge: anx7625: Use pm_runtime_force_{suspend, resume}

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 14d73fb1dd15..8325e8d0ee19 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1349,6 +1349,8 @@ static void anx7625_bridge_detach(struct drm_bridge *bridge)
 		mipi_dsi_detach(ctx->dsi);
 		mipi_dsi_device_unregister(ctx->dsi);
 	}
+	if (ctx->link)
+		device_link_del(ctx->link);
 }
 
 static int anx7625_bridge_attach(struct drm_bridge *bridge,
@@ -1373,17 +1375,33 @@ static int anx7625_bridge_attach(struct drm_bridge *bridge,
 		return err;
 	}
 
+	ctx->link = device_link_add(bridge->dev->dev, dev, DL_FLAG_STATELESS);
+	if (!ctx->link) {
+		DRM_DEV_ERROR(dev, "device link creation failed");
+		err = -EINVAL;
+		goto detach_dsi;
+	}
+
 	if (ctx->pdata.panel_bridge) {
 		err = drm_bridge_attach(bridge->encoder,
 					ctx->pdata.panel_bridge,
 					&ctx->bridge, flags);
 		if (err)
-			return err;
+			goto remove_device_link;
 	}
 
 	ctx->bridge_attached = 1;
 
 	return 0;
+
+remove_device_link:
+	device_link_del(ctx->link);
+detach_dsi:
+	if (ctx->dsi) {
+		mipi_dsi_detach(ctx->dsi);
+		mipi_dsi_device_unregister(ctx->dsi);
+	}
+	return err;
 }
 
 static enum drm_mode_status
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
index edbbfe410a56..299e62df6238 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.h
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
@@ -473,6 +473,7 @@ struct anx7625_data {
 	struct drm_connector *connector;
 	struct mipi_dsi_device *dsi;
 	struct drm_dp_aux aux;
+	struct device_link *link;
 };
 
 #endif  /* __ANX7625_H__ */